Emission control additive



United States Patent US. CI. 4469 5 Claims ABSTRACT OF THE DISCLOSUREIncrease of combustion chamber deposits and exhaust hydrocarbon emissionof internal combustion engines is reduced by operating the engine ongasoline containing ortho-substituted aromatic nitro compounds.

This invention relates to a fuel composition for use in internalcombustion engines which results in reduced hydrocarbon emission in theexhaust gas and a reduced amount of combustion chamber deposits. Inparticular, this invention relates to a liquid hydrocarbon fuelcontaining an aromatic nitro compound.

The exhaust gas of internal combustion engines contains some quantity ofunburned hydrocarbons. Hydrocarbons are reported by researchers to reactwith ozone in the atmosphere, forming irritants. Research has attributedphotochemical smog to the presence of hydrocarbons in the atmosphere.Thus, a need exists for a method to reduce the amount of hydrocarbonintroduced into the atmosphere from the exhaust gas of internalcombustion engines. Previous means of accomplishing this have beenthrough the secondary oxidation of the unburned exhaust hydrocarbonsemploying catalytic oxidizing methods or direct flame oxidation in theexhaust system. If the amount of unburned hydrocarbons initially in theexhaust can be reduced, the need for secondary oxidation is diminished.Previous attempts to reduce the initial hydrocarbon content of theexhaust gas have concentrated on mechanical methods such as improvedcarburetion. The present invention relates to a method of reducingexhaust emission and engine deposits through the use of a fuelcontaining an exhaust emission reducing additive.

An object of this invention is to provide an improved fuel composition.A further object is to provide a fuel composition which, when used tooperate an internal combustion engine, results in reduced hydrocarbonemission. A still further object is to provide a fuel that willsubstantially reduce the amount of deposits formed in the combustionchamber of engines.

These and other objects are accomplished by providing an improved fuelcomposition comprising a major portion of a liquid hydrocarbon fuel anda minor quantity, sutficient to reduce exhaust emission and enginedeposits, of an aromatic nitro compound having the formula:

wherein R is selected from the group consisting of alkyl radicals havingfrom 1-20 carbon atoms, aryl radicals having from 6-20 carbon atoms,aralkyl radicals having from 7-20 carbon atoms, alkanoyloxy radicalscontaining from 1-12 carbon atoms, alkoxy radicals containing from 1-12carbon atoms, hydroxyl radicals and halogens having an atomic No. from17-35, and R and R are selected from the group consisting of hydrogen,nitro radicals,

3,434,814 Patented Mar. 25, 1969 hydroxyl radicals, alkoxy radicalscontaining from 1-12 carbon atoms, alkyl radicals containing from 1-20carbon atoms, aryl radicals containing from 6-20 carbon atoms, andaralkyl radicals containing from 7-20 carbon atoms.

In more preferred embodiments of the invention, R in Formula I isselected from the group consisting of alkyl radicals having from 1-2-()carbon atoms, aryl radicals having from '6-20 carbon atoms, aralkylradicals having from 7-20 carbon atoms, alkanoyloxy radicals containingfrom 1-12 carbon atoms, alkoxy radicals containing from 1-12 carbonatoms, and halogens having an atomic No. from 17-35, and R and R areselected from the group consisting of hydrogen, nitro radicals, alkoxyradicals containing from 1-12 carbon atoms, alkyl radicals containingfrom 1-20 carbon atoms, aryl radicals containing from 6-20 carbon atomsand aralkyl radicals containing from 7-20 carbon atoms.

Not all nitro aromatics are useful in reducing exhaust emissions. Forexample, nitrobenzene itself causes an increase in both exhaust emissionand combustion chamber deposits. The useful aromatic nitro compounds arethose having some fuel solubility and an ortho substituent as shown inFormula I. Some examples of these aromatic nitro compounds are o-nitrotoluene, 2,6-dinitrochlorobenzene, 2,5-dimethoxy nitrobenzene,o-sec-dodecyl-nitrobenzene, Z-dodecoxy-4-methyl-nitrobenzene,2-methyl-4-hydroxy-5-tert-butyl-nitrobenzene,2-ch1oro-4-methoxy-nitrobenzene, 2-bromo-S-tert-eicosyl-nitrobenzene,Z-hexanoyloxy-4-phenyl-nitrobenzene, 2-methoxy-4-tertbutyl-S-hydroxy-nitrobenzene, Z-tert-octyl-6-chloro-nitrobenzene,2,4-dibromo-nitrobenzene, 2-(a-methylbenzyl)nitrobenzene,Z-acetoxy-S-tert-cetyl-nitrobenzene,2-methoxy-3,S-dichloro-nitrobenzene, 2,6-dinitro-chlorobenzene,2-dodecanoyloxy-4-tert-octadecyl-nitrobenzene,2-chloro-4-benzyl-nitrobenzene, 2 methyl 5-(2,4-ditertbutyl-u,adimethyIbenZyl)-nitrobenzene,1,3-dinitro-6-(2-methyl-4-sec-tridecylphenyl)benzene, and

the like.

Highly preferred aromatic nitro additives are1,4-dimethoxy-2-nitrobenzene, 2,4-dinitro-toluene and picryl acetate.

The additives of this invention can be used to reduce emissions andcombustion chamber deposits resulting from the use of a broad range ofliquid hydrocarbon fuels including both spark ignition and diesel fuels.It is especially useful in gasoline used in spark ignition engines.These liquid hydrocarbon fuels have a boiling range of from about toabout 400 F., and contain aliphatic, aromatic, olefinic and naphthenichydrocarbons. The hydrocarbon fuels may contain other materialsfrequently used in such fuels. For example, the fuels may containantiknock agents such as tetraethyllea d, tetramethyllead,triethylmethyllead, diethyldimethyllea'd, trimethylethyllead,tetravinyllead, triethylvinyllead, diethyldivinyllead,trivinylethyllead, ferrocene, methyl ferrocene, iron carbonyl,methylcyclopentadienyl manganese tricarbonyl, methylcyclopentadienylnickel nitrosyl, N,N-dimethylaniline, and the like. When metallicantiknock agents are employed the fuels generally contain a scavengingagent. A particularly useful scavenging agent when lead alkyls areemployed are the halohydrocarbons such as ethylenedichlo' ride,ethylenedibrornide, and the like. An especially useful fuel in thisinvention is a fuel containing from 0.5 to 6 grams of lead per gallon astetraethyllead and from 1.5 to 2.5 gram atoms of chlorine as achlorohydrocarbon per gram atom of lead and from 0.5 to 1.5 gram atomsof bromine as a bromohydrocarbon per gram atom of lead. The mostprefered chlorohydrocarbon is ethylenedichloride, and the most preferredbromohydrocarbon is ethylenedibromide.

The fuels can also contain deposit modifying agents such as phosphoruscontaining additives, for example, tricresylphosphate,cresyldiphenylphosphate, trimethylphosphate, ldimethylcresylphosphate,tris (,B-chloropropyl) phosphate, and the like.

The fuels frequently contain antioxidant additives such as 2,6 ditertbutylphenol; 2,6-di-tert-butyl-4-methylphenol;4,4'-methylenebis(2,6-di-tert-butylphenol); 2,2- methylenebis(4methyl-6-tert butylphenol); phenylenediamines; p-nonylphenol; mixedalkylated phenols, 4,4'-thiobis(3-methyl-6-tert butylphenol) and thelike.

Other materials can be present in the fuel such as deicers, metaldeactivators, pour point depressants, boron esters, nickel alkylphosphates and dyes.

The following examples illustrate the preparation of typical improvedfuel compositions of this invention.

EXAMPLE 1 To a blending vessel is added 1000 gallons of a gasolinehaving the following properties:

Boiling range F 101-375 Research octane number 93 Aromatics (volumepercent) 38 Olefinics do 10 Aliphatics do 52 To this gasoline is added atetraethyllead antiknock agent containing two gram atoms of chlorine asethylenedichlori de per gram atom of lead and one gram atom of bromineas ethylenedibromide per grams atom of lead. The quantity oftetraethyllead antiknock agent added is sufficient to provide 3.17 gramsof lead per gallon of fuel. There is then added suflrcientl-chloro-2,4-dinitrobenzene to give a concentration of 0.25 weightpercent. The mixture is agitated until thoroughly mixed, resulting in agasoline having reduced exhaust emission properties.

EXAMPLE 2 To a blending vessel is added 1000 gallons of a gasolinehaving the following properties:

Boiling range F 94-403 Research octane number 97 Aromatics (volumepercent) 62 Olefinics do Aliphatics -do 33 To this gasoline is added atetraethyllead antiknock mixture containing one theory of chlorine asethylenedichloride and 0.5 theory of bromine as ethylenedibromide. Aquantity sufficient to provide 2.12 grams of lead per gallon is added.There is also added, as an antioxidant, a mixture of butylated phenolscontaining about 75 percent 2,6-di-tert-butylphenol, such that thegasoline contains 0.1 weight percent of the antioxidant mixture. Then0.15 weight percent of 1,4-dimethoxy-2-nitrobenzene is added and themixture thoroughly stirred, resulting in a gasoline giving reducedemission and combustion chamber deposits weight when used to operate aspark ignition internal combustion engine.

Good results are also obtained in the above example when2,4-dinitro-toluene is employed as the emission and deposit reducingagent.

EXAMPLE 3 To a blending vessel is added 1000 gallons of a diesel fuelhaving a boiling range of from 430-572 F., and a cetane number of 47. Tothis is added 0.3 weight percent amyl nitrate as a cetane improver.There is then added 0.2 weight percent of picryl acetate, resulting in adiesel fuel having reduced exhaust emission properties.

In any of the previous examples, the forementioned emission reducingcompounds can be employed, giving fuels having reduced emissionproperties. Also, the concentrations may be varied from those shown. Ingeneral, a concentration of from about 0.05 to 3 weight percent of theemission reducing additive can be employed. A preferred concentrationrange is from about 0.1 to 1 weight percent, and a most useful range isfrom about 0.1 to 0.5 weight percent.

Tests have been conducted to demonstrate the useful exhaust emissionproperties of the present compounds. In these tests, a single cylinderoverhead valve engine, having a 10:1 compression ratio and a 36 cubicinch displacement, is operated on a typical commercial gasolinecontaining 3.17 grams of lead as a commercial tetraethyllead antiknockmixture containing one theory of chlorine as ethylenedichloride and 0.5theory of bromine as ethylenedibromide. One theory of either bromine orchlorine is two gram atoms of bromine or chlorine per gram atom of lead.The engine is idled for 45 seconds and then run at 50 percent wide openthrottle for 135 seconds under the following conditions.

Air/fuel ratio 13 R.p.m. 1370 Ignition timing BTC-.. 15

The above cycle is continuously repeated until both deposits andhydrocarbon emissions have stabilized. This usually requires from about-145 hours of operation. The hydrocarbon content of the exhaust gas isdetermined using a Beckman 109-A Flame Isomerization Detector, and thedeposits are determined by disassembling the engine, removing andweighing the deposits. The procedure is first carried out using a fuelwithout the emission reducing additive and then repeated on the samefuel containing an emission reducing additive. This is followed byanother test on the fuel, again without the emission additive, toreconfirm the baseline. Using this procedure, the following results interms of the percent reduction in exhaust hydrocarbon emission andengine deposits were obtained using emission reducing additives of thisinvention.

1 Gain average of two tests.

Cone. Additive 1:

Deposits As these results show, the emission reducing additives of thepresent invention effectively reduce both exhaust emission and enginedeposits. The reduction in deposits and emission was very significant.Deposit reduction ranged from 22-40 percent and emission reduction from14-25 percent. In contrast, nitrobenzene (not claimed as this invention)gave a sharp increase in both deposit weight and exhaust emission.

We claim:

1. A liquid hydrocarbon fuel of the gasoline boiling range havingreduced emission and deposit forming properties when used to operate aninternal combustion engine, said fuel comprising a major quantity of aliquid hydrocarbon of the gasoline boiling range and a minor amountsuflicient to reduce exhaust emissions and engine deposits of anaromatic nitro compound selected from the group consisting of1.4-dimethoxy-Z-nitrobenzene, 2,4-dinitrotoluene, and picryl acetate.

2. The composition of claim 1 containing from 0.5 to References Cited 6grams of lead per gallon as a tetraalkyllead antiknock, from 0.5 to 2theories of chlorine as ethylene dichloride UNITED STATES PATENTS andfrom 0.25 to 1.0 theory of bromine as ethylene- 11423050 7/1922 Tunison44 Momma 5 3,294,501 12/1966 Kawahara 44-75 XR 3. The composition ofclaim 1 wherein said aromatic nitro compound is1,4-dimethoxy-Z-nitrobenzene. DANIEL WYMAN P r 1mm y Examiner 4. Thecomposition of claim 1 wherein said aromatic W. J. SHINE, AssistantExaminer. nitro compound is 2,4-dinitro toluene.

5. The composition of claim 1 wherein said aromatic 10 US. Cl. X.R.nitro compound is picryl acetate, 44-57, 74, 75

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3 ,434,8l4

March 25 19 Michael Dubeck et al.

ed that error appears in the above identified It is certifi atent arehereby corrected as patent and that said Letters P shown below:

"1.4-" should read 1,4- Column 5, line Column 4, line 74,

d dibromide.

5, bromide. should rea Signed and sealed this 7th day of April 1970.

(SEAL) Attest:

WILLIAM E. SCHUYLER, 1

Edward M. Fletcher, Jr. Attesting Officer Commissioner of Patel

